Methods, Apparatus and Wireless Device for Transmitting and Receiving Data Blocks

1. A method of transmitting data from a transmitter, the method comprising: transmitting from the transmitter a plurality of protocol data units (PDUs), defined in a transmission window maintained by the transmitter, for receipt by a receiver; transmitting from the transmitter a status request to a said receiver for positive acknowledgement of successful receipt of the status request, the status request identifying a PDU; and updating the transmission window in the transmitter to remove the record of a particular PDU from the transmission window and to add a record of at least one different PDU to the transmission window upon receipt of a positive acknowledgement of receipt of that particular PDU or upon receipt of a positive acknowledgement of receipt of a status request relating to that particular PDU, the transmitter in this mode not retransmitting PDUs that are not acknowledged as received by said receiver.

2. A method according to claim 1 , wherein the status request is transmitted if positive acknowledgement of successful receipt of the PDU identified in the status request has not been received within a predetermined time period from transmission of the PDU.

3. A method according to claim 1 , wherein the status request is a status PDU having a POLL SUFI constituting the request for positive acknowledgement.

4. A method according to claim 1 , wherein the PDUs are AMD PDUs.

5. A method according to claim 1 , wherein the transmissions form pan of a multi-cell/carrier aggregation transmission.

6. A method of receiving PDUs at a receiver, the method comprising: receiving at the receiver a plurality of transmitted PDUs; receiving at the receiver from a transmitter a status request for positive acknowledgement of successful receipt of the status request, the status request identifying a particular PDU; the receiver sending from the receiver a positive acknowledgement of successful receipt of a PDU upon receipt of said PDU; and sending from the receiver a positive acknowledgement of successful receipt of a status request relating to a particular PDU upon receipt of said status request; the receiver in this mode not buffering received PDUs.

7. A method according to claim 6 , wherein the status request is a status PDU having a POLL SUFI constituting the request for positive acknowledgement.

8. A method according to claim 6 , wherein the positive acknowledgement identifies the corresponding PDU by reference to a sequence number of the PDU.

9. A method according to claim 6 , wherein the PDUs are AMD PDUs.

10. A method according to claim 6 , wherein the transmissions to the receiver form part of a multi-cell/carrier aggregation transmission.

11. A method according to claim 6 , the method further comprising monitoring by the receiver for dropped PDUs which are not successfully received and initiating a switch to a different mode of transmission if the number of dropped PDUs occurring in a predetermined time period exceeds a predetermined number.

12. A method according to claim 11 , wherein the receiver considers PDUs that were not successfully received before the switch to the different mode of transmission as lost PDUs and updates state variables maintained by the receiver accordingly.

13. A processing system for a transmitter that transmits data to a receiver, the processing system comprising at least one processor and at least one memory including computer program code and being constructed and arranged to cause: transmission of a plurality of PDUs, defined in a transmission window maintained by the transmitter, for receipt by a receiver; transmission of a status request to a said receiver for positive acknowledgement of successful receipt of the status request, the status request identifying a PDU; and updating of the transmission window to remove the record of a particular PDU from the transmission window and to add a record of at least one different PDU to the transmission window upon receipt of a positive acknowledgement of receipt of that particular PDU or upon receipt of a positive acknowledgement of receipt of a status request relating to that particular PDU, the transmitter in this mode not retransmitting PDUs that are not acknowledged as received by said receiver.

14. A processing system according to claim 13 , wherein the processing system is constructed and arranged such that the status request is transmitted if positive acknowledgement of successful receipt of the PDU identified in the status request has not been received within a predetermined time period from transmission of the PDU.

15. A processing system according to claim 13 , wherein the processing system is constructed and arranged such that the status request is a status PDU having a POLL SUFI constituting the request for positive acknowledgement.

16. A processing system according to claim 13 , wherein the processing system is constructed and arranged such that the PDUs are AMD PDUs.

17. A wireless device having a processing system according to claim 13 .

18. A processing system for a receiver that receives PDUs transmitted by a transmitter, the processing system comprising at least one processor and at least one memory including computer program code and being constructed and arranged to cause: a said receiver to be able to receive a plurality of transmitted PDUs; a said receiver to be able to receive a status request for positive acknowledgement of successful receipt of the status request, the status request identifying a particular PDU; a said receiver to send a positive acknowledgement of successful receipt of a PDU upon receipt of said PDU; and a said receiver to send a positive acknowledgement of successful receipt of a status request relating to a particular PDU upon receipt of said status request; the receiver in this mode not buffering received PDUs.

19. A processing system according to claim 18 , wherein the processing system is constructed and arranged such that the status request is a status PDU having a POLL SUFI constituting the request for positive acknowledgement.

20. A processing system according to claim 18 , wherein the processing system is constructed and arranged such that the positive acknowledgement identifies the corresponding PDU by reference to a sequence number of the PDU.

21. A processing system according to claim 18 , wherein the processing system is constructed and arranged such that the PDUs are AMD PDUs.

22. A processing system according to claim 18 , wherein the processing system is constructed and arranged such that the receiver monitors for dropped PDUs which are not successfully received and initiates a switch to a different mode of transmission if the number of dropped PDUs occurring in a predetermined time period exceeds a predetermined number.

23. A processing system according to claim 22 , wherein the processing system is constructed and arranged such that the receiver considers PDUs that were not successfully received before the switch to the different mode of transmission as lost PDUs and updates state variables maintained by the receiver accordingly.

24. A wireless device having a processing system according to claim 18 .

25. A wireless device that is capable of wirelessly transmitting signals to and receiving signals from another wireless device, the device comprising at least one processor and at least one memory including computer program code and being constructed and arranged such that: when transmitting, the device: transmits a plurality of PDUs, defined in a transmission window maintained by the transmitter, for receipt by a said other wireless device; transmits a status request to a said other wireless device for positive acknowledgement of successful receipt of the status request, the status request identifying a PDU; and updates the transmission window to remove the record of a particular PDU from the transmission window and to add a record of at least one different PDU to the transmission window upon receipt of a positive acknowledgement of receipt of that particular PDU or upon receipt of a positive acknowledgement of receipt of a status request relating to that particular PDU, the transmitter in this mode not retransmitting PDUs that are not acknowledged as received by said receiver; and, when receiving, the device: receives a plurality of transmitted PDUs from a said other wireless device; receives from a said other wireless device a status request for positive acknowledgement of successful receipt of the status request, the status request identifying a particular PDU; sends a positive acknowledgement of successful receipt of a PDU upon receipt of said PDU; and sends a positive acknowledgement of successful receipt of a status request relating to a particular PDU upon receipt of said status request; the receiver in this mode not buffering received PDUs.

26. A memory tangibly storing computer program comprising code for transmitting data from a transmitter to a receiver such that when the computer program is executed on a computing device, the computing device is arranged to cause a wireless device to: transmit a plurality of protocol data units (PDUs), defined in a transmission window maintained by a transmitter, for receipt by a receiver; transmit a status request to a said receiver for positive acknowledgement of successful receipt of the status request, the status request identifying a PDU; and update the transmission window to remove the record of a particular PDU from the transmission window and to add a record of at least one different PDU to the transmission window upon receipt of a positive acknowledgement of receipt of that particular PDU or upon receipt of a positive acknowledgement of receipt of a status request relating to that particular PDU, the transmitter in this mode not retransmitting PDUs that are not acknowledged as received by said receiver.

27. A memory tangibly storing computer program comprising code for receiving PDUs transmitted by a transmitter to a receiver such that when the computer program is executed on a computing device, the computing device is arranged to cause a wireless device to: receive at a receiver a plurality of transmitted PDUs; receive from a transmitter a status request for positive acknowledgement of successful receipt of the status request, the status request identifying a particular PDU; send a positive acknowledgement of successful receipt of a PDU upon receipt of said PDU; and send a positive acknowledgement or successful receipt of a status request relating to a particular PDU upon receipt of said status request; where the receiver in this mode not buffering received PDUs.